It got NFL quarterback Michael Vick thrown into prison three years ago, but it's perfectly legal in the virtual world.
That's the idea behind a new app called "Dog Wars," a new video game available for free on the Android smart phone market.
Critics say the game perpetuates cruelty against animals and teaches people how to prepare dogs for fights.
Paul Weber is the president of the Los Angeles Police Protective League. The union representing local police officers is one of many organizations outraged by the game.
"It sends the wrong message to our kids, that this is acceptable behavior and it should be emulated," Weber said. "That this is something to be emulated or respected is really repugnant."
The concept of "Dog Wars" is simple. You feed, train and fight your virtual dog against other players who do the same. The creators say it's just a fantasy role playing game, much like those in which human characters fight to the death.
In a statement on their website, app maker Kage Games said: "We do not condone violence toward animals or humans and we are confident in humankind's ability to distinguish between a game and the consequences of real life."
While dozens of people have posted comments on the company's website calling for the game to be banned the makers responded by referencing the app "Angry Birds," saying: "just go slingshot some virtual birds to kill some virtual pigs."